While Evil queen's holiday was his first official work, he has done numerous other stuff while learning from EQH. If you've been following this webtoon, you would have noticed a steady improvement. Simply compare the first episode and the last.

The difference is very clear.

Having said that, nobody draws a webtoon for years without a motive/a goal. And Rusielin had a goal. His goal was apparently to earn a living via drawing webtoons. (The dream for most of comic artists which probably only 0.1% reach.)

And in order to get a job as a webtoon artist, he wanted some sort of portfolio. And that is where Evil Queen's holiday comes in. It appeared that his first planned step was getting approved as an official webtoon artist for PyeongChang 2018 Olympic Winter Games.